Blamed because they can't do their jobs

This morning we went to fill up our car at sasol, my daughter wanted a juice so we went into the shop at the garage. I told the attendant at the till to charge the petrol as well and he put my sale through for het juice. I paid and went out. In front of the shopI helped my daughter into the car fastened hetlr safety belt opened her juice, and off we went. Later this afternoon the police comes to my house they realised they never charged my petrol so my question we were there for about 10 minutes after paying why not come to me and tell me they made a mistake?? No they had to be dramatic and send the police??? We stop there every single Saturday before work we fill up our cars there and this is the service that we get?